Corona device and method for using same

Abstract

A corona discharge device is disclosed in which a cylindrical shell made of a dielectric material is mounted around a rotatable axle. Electrodes are arranged inside and outside of the shell so as to provide a corona discharge across a material to improve its surface qualities. A method of corona discharge treatment with the above apparatus is also disclosed.

What is claimed is: 
     
       1. A corona discharge device for charging the surface of a material which comprises: a. a rotatable roll comprising a cylindrical shell made of a dielectric material;   b. at least one first electrode located outside said roll;   c. at least one second electrode located within said roll, said first and second electrodes being arranged along the cylindrical contour of said shell with said second electrodes within said shell being in contact with said shell, and one of said first or second electrodes being adapted for carrying electrical current and the other being adapted to be grounded as a counter electrode; and   d. a spring means for pressing said second electrodes within said shell against the inside surface thereof.   
     
     
       2. The corona discharge device as defined by claim 1, wherein said rotatable roll further comprises an axle having discs mounted thereon, arranged in spaced relation to support said cylindrical shell. 
     
     
       3. The corona discharge device as defined by claim 2, wherein said axle is hollow. 
     
     
       4. The corona discharge device as defined by claim 3, wherein said axle is provided with inlet bores leading to the interior of said shell. 
     
     
       5. The corona discharge device as defined by claim 4, wherein said cylindrical shell is comprised of reinforced synthetic resin. 
     
     
       6. The corona discharge device as defined by claim 5, wherein said electrodes within said shell are off-set wtih respect to said electrodes outside said shell such that the corona discharge which results follows an oblique path through the wall of said shell. 
     
     
       7. The corona discharge device as defined by claim 5, wherein said electrodes inside and outside said shell are arranged such that said electrodes inside and outside said shell are offset from one another and further such that said electrodes are arranged such that when one set of electrodes is electrified and the other set is grounded, a discharge flows between two of said electrodes on one side of said shell and one of said electrodes on the other side of said shell. 
     
     
       8. The corona discharge device as defined by claim 1, wherein at least some of said electrodes are wire electrodes and said wire electrodes are arranged approximately parallel to the longitudinal axis of said axle. 
     
     
       9. The corona discharge device as defined by claim 8, wherein all of said electrodes are wire electrodes. 
     
     
       10. The corona discharge device as defined by claim 8, wherein said electrodes within said shell are off-set with respect to said electrodes outside said shell such that the corona discharage which results follows an oblique path through the wall of said shell. 
     
     
       11. The corona discharge device as defined by claim 8, wherein said electrodes inside and outside said shell are arranged such that said electrodes inside and outside said shell are offset from one another and further such that said electrodes are arranged such that when one set of electrodes is electrified and the other set is grounded, a discharge flows between two of said electrodes on one side of said shell and one of said electrodes on the other side of said shell. 
     
     
       12. The corona discharge device as defined by claim 1, wherein said cylindrical shell is comprised of reinforced synthetic resin. 
     
     
       13. The corona discharge device as defined by claim 1, wherein said shell is rotatably mounted around said axle. 
     
     
       14. The corona discharge device as defined by claim 1, wherein said roll is in contact with metal rolls for cooling said roll. 
     
     
       15. A corona discharge device for charging the surface of a material which comprises: a. a rotatable roll comprising a cylindrical shell made of a dielectric material;   b. at least one metal roll in contact with said cylindrical shell for cooling said roll;   c. at least one first electrode located outside said roll; and   d. at least one second electrode located within said roll, one of said first or second electrodes being adapted for carrying electrical current and the other being adapted to be grounded as a counter electrode.   
     
     
       16. The corona discharge device of claim 15, wherein said electrodes outside and inside said shell are arranged along the cylindrical contour of the shell. 
     
     
       17. The corona discharge device of claim 16, wherein said electrodes within said shell are in contact with the inside of said shell. 
     
     
       18. The corona discharge device of claim 17, further comprising a spring means for pressing said electrode within said shell against the inside of said shell. 
     
     
       19. The corona discharge device of claim 15, wherein said rotatable roll further comprises an axle having discs mounted thereon, arranged in spaced relation to support said cylindrical shell. 
     
     
       20. The corona discharge device of claim 19, wherein said axle is hollow. 
     
     
       21. The corona discharge device of claim 20, wherein said axle is provided with inlet bores leading to the interior of said shell. 
     
     
       22. The corona discharge device of claim 15, wherein at least some of said electrodes are wire electrodes and said wire electrodes are wire electrodes and said wire electrodes are arranged approximately parallel to the longitudinal axis of said axle. 
     
     
       23. The corona discharge device of claim 22, wherein said electrodes within said shell are offset with respect to said electrodes outside said shell such that the corona discharge which results follows an oblique path through the wall of said shell. 
     
     
       24. The corona discharge device of claim 22, wherein said electrodes inside and outside said shell are arranged such that said electrodes inside and outside said shell are offset from one another and further such that said electrodes are arranged such that when one set of electrodes is electrified and the other set is grounded, a discharge flows between two of said electrodes on one side of said shell and one of said electrodes on the other side of said shell. 
     
     
       25. The corona discharge device of claim 15, wherein said cylindrical shell is comprised of reinforced synthetic resin.